need transmission schooling

[GuitarGuy]

hello all, guitar guy here and I am needing info on 727 transmissions. I have a 72 demon I am restoring and will need to get a transmission core soon. the car will have a semi built 360 to start with, then I will install my 340 when I am done building it probably in about 2 years. the car will be a weekend driver although I will drive it as much as I can. the 340 will not be race orientated but pretty stout. I have a set of w2 econo heads and a strip dominator intake, that will be used. now to the question . I have been told that I will have to get a specific 727 for use with 340 witch wont work with the 360. so I need you guys to set me straight on what core I need to be looking for as I am pretty confused.



thank you in advance Ray

 

[moper]

The transmissions are the same. It's the convertors that would be different because the 360 is externally balanced and the factory did that by adding weight to the convertor. You can get a flexplate now for the 360, so you can use a convertor that would work with the 340. But - from what you describe, you should plan to replace the convertor when you build the 340 anyway...

 

[cannucky]

If you have a 904 for it now you can throw a race rebuild in it for the same price as buying/building a 727 and end up with more power to the wheels than you will get with the 727 and a lighter car as well .

 

[AJ/FormS]

Yeah, most every thing behind the flexplate could be the same.
Its the F-plates which are engine specific; that is one for the 360,and one for the 340; unless both are internally balanced, in which case they could be the same.
Convertors could be the same then, but could also be very engine specific as to stall speeds,depending on the engine builds.Eg. the stout 340 will need a different TC than a stockish 360.
Build the tranny now, and it will work on either, with only small changes to the pressure circuits later.If you have any year, non loc-up, A999, it can be the same, mostly.lol.
Whichever core you get, be sure to also get ALL the KD mechanism, for a 4bbl set up and fairly year specific to your year and model.( 68 to 72 A-body.) Personally I like the PartThrottle KD VBs that came on line in the early 70s. My 73 had it.worked really nice with a TFII kit. Not a deal breaker though.
The valve bodies could go either way, depending partly on personal preference and partly on application.
So your information could be right or wrong.
Hope that helps.

 

[fishy68]

As mentioned the transmissions are the same for a 340 and 360. Just the converter is different. If you want to stay with a 727 the 71-73 is generally considered the best to start with but from what you describe I don't see why a properly built 904 wouldn't do the trick. Like Cannucky said you'll get more HP to the ground with a 904. Less rotating mass to absorb HP